Ultra-processed foods increase risk of CVD and mortality, claims study
Ultra-processed foods account for 58% of total energy in the average U.S. diet, but diet is a modifiable risk factor in the prevention of cardiovascular disease (CVD). A study published in the Journal of the American College of Cardiology found that higher consumption of ultra-processed foods is associated with an increased risk of CVD incidence and mortality, with each additional daily serving found to further increase risk.
"The consumption of ultra-processed foods makes up over half of the daily calories in the average American diet and are increasingly consumed worldwide. As poor diet is a major modifiable risk factor for heart disease, it represents a critical target in prevention efforts," said Filippa Juul, MS, PhD, a faculty fellow at the New York University School of Public Health and lead author of the study. "Our findings add to a growing body of evidence suggesting cardiovascular benefits of limiting ultra-processed foods. Ultra-processed foods are ubiquitous and include many foods that are marketed as healthy, such as protein bars, breakfast cereals and most industrially produced breads. Population-wide strategies such as taxation on sugar-sweetened beverages and other ultra-processed foods and recommendations regarding processing levels in national dietary guidelines are needed to reduce the intake of ultra-processed foods. Of course, we must also implement policies that increase the availability, accessibility and affordability of nutritious, minimally processed foods, especially in disadvantaged populations. At the clinical level, there is a need for increased commitment to individualized nutrition counseling for adopting sustainable heart-healthy diets."
When foods are processed it may remove beneficial nutrients and other naturally occurring benefits, while adding non-beneficial nutrients and food additives. Processing also changes the physical structure of foods. The consumption of ultra-processed foods is linked with being overweight/obese, high blood pressure, metabolic syndrome and Type 2 diabetes.
Researchers used data from the Framingham Offspring Study to examine the role ultra-processed foods play in cardiovascular disease. After excluding participants with pre-existing CVD or missing data, the study included 3,003 middle-aged adults (on average 53.5 years). Over half of participants were female, 33.1% had undergone 16 years or more of education and two-thirds were either former or current smokers. Study participants were primarily Caucasian. Overall, 5.8% had diabetes and 19% had high blood pressure; prevalence was higher among participants who were high consumers of ultra-processed foods compared to low consumers.
Diet was assessed by mail using a food questionnaire where participants reported the frequency of consumption of certain foods in the previous year, with options ranging from <1 serving/months to ?6 servings/day. During in-person examinations trained personnel reviewed the questionnaires. The U.S. Department of Agriculture nutrient database was used to calculate nutrient intakes from reported dietary intakes.
Using a modified version of the NOVA framework, which classifies foods according to the extent and purpose of the industrial processing they undergo, researchers classified food questionnaire food items into five categories:
- Unprocessed or minimally processed foods, including fresh, dry or frozen plant and animal foods
- Processed culinary ingredients, including table sugar, oils, fats, salts and other items used in kitchens to make culinary preparations
- Processed foods, including foods such as canned fish and vegetables and artisanal cheeses
- Ultra-processed foods, including industrial formulations made with no or minimal whole foods and produced with additives such as flavorings or preservatives
- Culinary preparations, which encompassed mixed dishes that were indicated to be homemade or assumed to be homemade due to lack of detailed information
The researchers examined incident hard CVD (sudden and non-sudden coronary death, heart attack and fatal/non-fatal stroke) and hard coronary heart disease (sudden and non-sudden coronary death and heart attack). During an average of 18 years of follow-up, a total of 648 cardiovascular events occurred, including 251 cases of hard CVD and 163 cases of hard coronary heart disease (CHD). There were 713 deaths during the follow-up period, including 108 CVD deaths. Participants with the highest intakes of ultra-processed foods had higher incident rates compared to those consuming the least amount of ultra-processed foods.
Each daily serving of ultra-processed food was associated with a 7% increase in the risk of hard CVD, a 9% increase in the risk of hard CHD, a 5% increase in overall CVD and a 9% increased risk in cardiovascular disease mortality. Researchers also found that intake of bread was associated with an increased risk of hard CVD, hard CHD and overall mortality, while ultra-processed meat intake was associated with an increased risk of hard CVD and overall CVD. Salty snack foods were associated with increased risk of hard CVD and CHD, while consumption of low-calorie soft drinks were associated with increased risk of overall CVD.
In an accompanying editorial, Robert J. Ostfeld, MD, MSc, and Kathleen E. Allen, MS, RD, wrote, "Recognizing that multiple factors feed into individual food choice, where do we go from here? Ultimately, the goal should be to make the unhealthy choice the hard choice and the healthy choice the easy choice."
Study limitations include the observational nature of the study, as well as the potential for measurement error in dietary assessment and under- and over-estimation of ultra-processed food intake due to misclassification. Additionally, the participants in the Framingham Offspring Study are primarily Caucasian and have higher educational levels and income than the general U.S. population, which limits the generalizability of the findings.